Method of forming glass-ceramic cooktop construction

ABSTRACT

A smooth cooktop construction and method of forming the same wherein a glass-ceramic panel is mounted in a frame and secured therein by means of a burner box structure which further serves to secure a control panel of the cooktop in the frame. A subassembly of electric burner elements mounted in insulators is provided in a mounting tray which is secured to the burner box structure with the insulators engaging the underside of the glass-ceramic panel. The insulators are mounted in the tray by means of sharp securing elements urged into the sidewalls of the insulators retaining the insulators in engagement with sidewall portions of the tray. This subassembly is adjustably secured to the burner box structure. A control panel is also secured to the frame by means of the burner box structure permitting facilitated installation of the control switches and indicator lights. Facilitated connection of the electrical wiring is also provided. The cooktop structure is assembled in an inverted position on a suitable assembly fixture for facilitated assembly.

United States Patent 1 1 Boner [4 1 Oct. 1, 1974 [75] Inventor: John T. Doner, Marion, Ohio [73] Assignee: Whirlpool Corporation, Benton Harbor, Mich.

[22] Filed: Nov. 2, 1973 [21] Appl. No: 412,328

[52] 11.8. C1 29/611, 29/469, 219/459, 219/463, 219/464 [51] int. Cl. H05b 3/00 [58] Field of Search 29/611, 469; 219/464, 446, 219/459, 463,521, 537

Primary ExaminerCharles W. Lanham Assistant Examiner-V. A. DiPalma Attorney, Agent, or Firm-Wegner, Stellman, McCord, Wiles & Wood [57] ABSTRACT A smooth cooktop construction and method of forming the same wherein a glass-ceramic panel is mounted in a frame and secured therein by means of a burner box structure which further serves to secure a control panel of the cooktop in the frame. A subassembly of electric burner elements mounted in insulators is provided in a mounting tray which is secured to the burner box structure with the insulators engaging the underside of the glass-ceramic panel. The insulators are mounted in the tray by means of sharp securing elements urged into the sidewalls of the insulators retaining the insulators in engagement with sidewall portions of the tray. This subassembly is adjustably secured to the burner box structure. A control panel is also secured to the frame by means of the burner box structure permitting facilitated installation of the control switches and indicator lights. Facilitated connection of the electrical wiring is also provided. The cooktop structure is assembled in an inverted position on a suitable assembly fixture for facilitated assembly.

14 Claims, 10 Drawing Figures m m 5 ww 3 mm sww F WENI am 11914 sum 1 or A PAIEME ucr H974 ,sumsofd BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to smooth surface cooktops and in particular to glass-ceramic cooktops and meth ods of forming the same.

2. Description of the Prior Art In smooth cooktops, a glass-ceramic panel is pro vided as the heating surface with the panel being heated from below by a suitable electric coil heater carried in a suitable insulator closely subjacent the glassceramic panel. In one form of such cooktop, a control panel is disposed alongside the cooking surface panel with the controls and indicating lights being disposed subjacent the control panel portion. An example of a cooktop utilizing such a heater coil construction is shown in US. Letters Pat. No. 3,612,829 of Jesse L. Evans, et al. In the Evans, et al, patent, resilient means are provided for urging heated blocks of refractoryfiber material in heat sealed cushion contact with the undersurface of the cooking panel.

Another patent generally similar thereto is that of Homer W. Deaton, et al, US. Letters Pat. No. 3,624,352 utilizing a surface temperature limiting device including a thermostat controlled by the temperature of the bracket flanges.

Other heating means generally of this type are disclosed in US. Letters Pat. Nos. 2,637,800 of K. M. Hammell and 2,260,165 of E. N. Calhoun.

SUMMARY OF THE INVENTION The present invention comprehends an improved smooth cooktop construction which is simple and economical of construction. The cooktop utilizes a number of subassemblies which may be adjustably secured into the overall construction for facilitated assembly. In one such subassembly, the electric heating elements are installed in a tray by means of supporting insulators. The insulators are secured to the tray by sharp retaining elements pressed into the sidewalls of the insulators and holding the insulators against a plurality of surfaces of the tray sidewalls. At least one of the sharp securing elements may be formed integrally with one of the tray sidewalls.

The cooktop is assembled in an inverted position on a suitable fixture. Thus, the cooking surface panel is installed on the frame carried on the fixture. A sealing gasket may be provided about the panel and the gasket retained in association with the frame by means of the burner box subsequently secured to the frame.

The burner box may include a dividing wall dividing the burner box space into two adjacent portions. A control panel may be mounted to the frame and secured thereto also by the burner box structure. The control switches and indicator light means may be mounted in the burner box space below the control panel. The heating coil tray may be secured to the dividing wall.

The electric wiring of the cooktop is facilitated by means of a wiring harness package. An electric cable clamp may be attached to the burner box bottom for facilitating connection of the electric cable wires. The heating elements are provided with terminals at the bottom thereof extending through the tray bottom for facilitated electrical connection. The electric terminal block providing support for the electric terminals is secured to the tray with a single screw. for facilitated installation.

Thus, the invention comprehends a cooktop construction which is extremely simple and economical of construction while yet providing the highly desirable advantages discussed above.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of the invention will be apparent from the following description taken in connection with the accompany drawing wherein:

FIG. 1 is a perspective view of a cooktop embodying the invention mounted in a portion of a kitchen cabinet;

FIG. 2 is an enlarged transverse vertical section thereof;

FIG. 3 is a fore-and-aft vertical section thereof;

FIG. 4 is a top plan view of the heating coil subassemy;

FIG. 5 is a fragmentary enlarged vertical section taken substantially along the line 5-5 of FIG. 4;

FIG. 6 is a fragmentary enlarged vertical section taken substantially along the line 6-6 of FIG. 4;

FIG. 7 is a perspective view illustrating a first step in the assembly of the cooktop;

FIG. 8 is a perspective view illustrating a subsequent I step in the assembly thereof;

FIG. 9 is a perspective view illustrating a further subsequent step; and

FIG. 10 is a perspective view illustrating a still further subsequent step in the assembly thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the exemplary embodiment of the invention as disclosed in the drawings, a smooth cooktop generally designated 10 is shown mounted in a portion of a cabinet 11 which, illustratively, may comprise a conventional kitchen counter cabinet. The cooktop is adapted for selective use as a drop-in range unit, or in a set-in range, or in a freestanding range, as desired.

As shown in FIG. l, the cooktop comprises a smooth cooktop defined by a cooking panel 12 illustratively comprising a glass-ceramic panel of conventional construction. The panel is set in a frame 13 which, as shown in FIG. 1, overlies the upper surface 14 of the counter. v

The frame may include a divider strip 15 for separating the panel 12 from a control panel 16 also set into the frame. As shown, the control panel may include a plurality of control knobs 17 for controlling heating of preselected areas 18 of the panel 12 by suitable heating elements 19 mounted subjacent the panel, as illustrated in FIG. 2. Control panel 16 may be formed of a tempered glass material and may be provided with indicating portions 20 to be suitably illuminated for indicating the energization of the selected burner areas 18 by corresponding manipulation of the control knobs 17 controlling adjustable switches 21, as shown in FIG. 2.

The invention comprehends an improved cooktop construction and method of forming the same which is extremely simple and economical. More specifically, the cooktop construction utilizes subassemblies which are adjustably associated permitting facilitated assembly of the entire unit by means of a simple fixture. As

shown in FIGS. 2 and 3, the cooktop includes burner box means 22 including sidewalls 23, 24, 25 and 26, and a dividing wall 27 extending across the burner box space 28 defined by the sidewalls 23-26 and dividing the space into a cooking space portion 29 and control space portion 30, as shown in FIG. 2. Divider wall 27, as shown in FIG. 8, extends between front sidewall 23 and rear sidewall 24 and includes a pair of mounting bosses 31 aligned with similar bosses 32 on left sidewall 25. The sidewalls may be provided adjacent their lower edges 33 with a plurality of louvers 34 for venting the burner box space 28.

The heating elements 19 are carried in a box-like tray 35 in cooking space 29. As shown in FIG. 2, tray 35 includes a left sidewall 36 secured to mounting boss 32 and a right sidewall 37 secured to mounting boss 31 supporting the tray adjustably under the panel 12 in the upper portion of cooking space 29.

As further shown in FIG. 2, the control switches 21 and indicating lights 38 of control 39 are'carried on a downwardly opening box-like control tray 40 within control space 30.

The heating elements 19 are subassembled in tray 35 for facilitated installation in the cooktop. As shown in FIGS. 4-6, the heating unit assembly generally desig nated 41 may include four heating elements 19, each defined by an electric heating coil 42 mounted in an insulator 43 provided with a spiral groove 44 receiving the heating coil 42. In the illustrated embodiment. the insulators 43 may be formed of a high reflectance, vacuum formed, short fiber alumina silica insulation. The insulators may be cast of such material to provide lightweight, heat resistant insulating supports for the heating coils.

Connecting wires 45 and 46 are brought from the opposite ends 47 and 48 of the heating coil outwardly to a terminal block 49. As shown in FIG. 5, each terminal block 49 includes a pair of terminals 50 extending downwardly through the bottom wall 51 of the tray 35 for facilitated electrical connection to the heating coils in the assembly of the cooktop. Each connector 49 is secured to the tray wall 51 by a single screw 52 providing further facilitated assembly of the unit.

As shown in FIG. 4, each insulator 43 includes a pair of flat surfaces 53 and 54 faeially engaging the right angularly extending sidewalls of the tray 35 at the corners 55 thereof, and more specifically, engaging portions 56 and 57 spaced from the corner edge 58. The insulators carrying the heating coils are fixedly secured in the tray corners by means of sharp retaining elements 59 and 60. Retaining elements 59 may comprise inturned tabs formed in the sidewall portions 57 of the tray sidewall and projecting into the insulating material of the insulator 43, as shown in FIG. 6. Retaining elements 60 may comprise turned portions of a retaining clip 61 secured to the tray bottom 51 by suitable means such as screw 62. Retaining elements 60 engage a portion of the insulator 43 generally oppositely of the surfaces 53 and 54 and cooperate with the retaining element 59 in locking the insulating elements firmly inthe corner portion as illustrated in FIG. 4.

As further shown in FIG. 4, the bottom wall 51 of tray 35 may be provided with a radiating embossment 63 reinforcing the bottom wall.

As shown in FIGS. 5 and 6, the upper edge 64 of the outer wall 65 of each insulator 43 projects above the top edge 66 of the sidewalls of the tray 35. Thus, when the tray is mounted to the bosses 31 and 32. the upper edge 66 of the tray is spaced slightly below panel 12 when the upper edge 64 of the insulators engages the undersurface 67 of panel 12. Vertical adjustment of the tray is permitted by provision of elongated slot-type openings 68 in the bosses 31 and 32, as shown in FIG. 3, permitting the tray to be secured to the burner box walls 25 and 27 by suitable screws 31a and 3211 with the heater assembly 41 disposed as shown in FIGS. 2 and 3.

The assembly of the cooktop is readily effected in a novel and simple manner, as shown in FIGS. 710, wherein frame 13 is firstly set on a suitable fixture 69 with the exposed trim portion 70 lowermost and with a turned flange portion 71 thereof projecting upwardly. As shown in FIG. 7, the frame includes the divider strip 15. The divider strip 15 similarly includes a trim portion 72 and a mounting flange portion 73. The glassceramic panel 12 is provided with a peripheral gasket 74 and the control panel 16 is similarly provided with a peripheral gasket 75 and then placed in the frame to rest on the trim portions 70 and 72.

In the next step, as seen in FIG. 8, the sidewalls 23, 24, 25 and 26 of the burner box are installed on the frame inwardly of the flange portion 71 to rest on the inturned trim portions 70. The dividing wall 27 is mounted to the divider strip 15 and each of the sidewalls and divider wall is secured to the frame by suitable screws 76 to define a burner box assembly 77, as shown in FIG. 8.

Sidewalls 23 and 24 may be suitably slotted to pass the opposite ends of the divider strip 15 in assembling the burner box structure 77, as shown.

Heating unit assembly 41 is then installed in an inverted position in the burner box space 29 to the left of divider wall 27, as shown in FIG. 9.

As discussed above. the burner box assembly is secured in position with the projecting edge 66 of the insulators engaging the underside 67 of panel 12 and secured in place by suitable screws 31a and 32a extended through the slotted openings 68 of the bosses 31 and 32. Similarly, the control assembly 40 is installed in an inverted position in the control space 30 to the right of divider wall 27 and suitably secured to the burner box by suitable screws 78 to be disposed subjacent the control panel 16 as shown in FIG. 2.

Wiring 79 between the heating element terminals 50, the indicator lights 38 and control switches 21 is then completed by means of a suitable color coded wiring harness package (not shown). The wires 80 may be brought out through a conventional electric cable clamp 81 in a bottom wall 82 which may be secured across the lower ends of the burner box assembly 77 by suitable screws 83 as shown in FIG. 10.

Mounting of the side walls 23, 24, 25 and 26 and divider wall 27 to the frame further serves to secure the panels 12 and 16 and the peripheral gaskets 74 and 75 thereof to the frame as illustrated in FIGS. 3 and 4. Thus, each of the sidewalls and divider wall may be provided with a turned flange 84 engaging the gasket to provide a cushioned mounting of the burner box and panels.

Upon completion of the subassembly of the cooktop as shown in FIG. 10, the cooktop may be removed from the fixture 69 and turned top uppermost permitting the control knobs 17 to be installed on the switch shafts 85 to complete the assembly of the cooktop.

In installations such as freestanding ranges. the bottom wall 82 of the burner box may be omitted. Thus, the cooktop is adapted for use not only as a drop-in unit, but also as a set-in or freestanding range unit.

The assembly of cooktop is facilitated by utilization of the burner box walls as the means for retaining the gasketed panels 12 and 16 in place on the frame. Adjustability in the mounting of the heating unit assembly 41 to the burner box walls further simplifies and facilitates assembly of the cooktop. Facilitated mounting of the heating unit insulators in the heating unit tray further simplifies the assembly while yet providing accurate positioning of the heating elements relative to the underside of the heating panel 12 in the completed cooktop.

As the heating unit terminals 50 are brought out through the bottom wall 51 of the heating unit, facilitated electrical connection is provided. The adjustability of the mounting of the tray permits for a lower cost construction in obviating the need for high tolerances in the dimensions of the heating unit element while yet a positive firm engagement between the heating unit insulators and the cooking panel is assured.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by, the invention.

I claim:

l. The method of assembling a cooktop comprising the steps of:

providing a cooktop frame member in an inverted position;

placing a glass-ceramic panel member on said frame;

securing burner box side members to the frame to define a burner box space and retain the panel member thereto; subassembling a plurality of surface heating elements each including terminal means; attaching said plurality of the subassembled surface elements to a tray; placing the tray assembly in an inverted disposition in said burner box space with said surface elements bearing against the plate member; fastening the tray assembly to the burner box side members; and connecting electrical wires to the terminal means. 2. The method of assembling a cooktop of claim 1 further including the step of mounting a gasket to the periphery of said plate member prior to placing it in said frame, and causing said burner box side members to retain the gasket to the frame.

3. The method of assembling a cooktop of claim 1 further including the step of placing a control panel on said frame adjacent said panel member, and securing said control panel thereto by means of said burner box side members.

4. The method of assembling a cooktop of claim 1 wherein said tray assembly is adjustably fixedly secured to said burner box side members.

5. The method of assembling a cooktop of claim ll further including the step of providing an electrical cable clamp through which said electrical wires are passed.

6. The method of assembling a cooktop of claim 1 further including the step of securing a bottom wall to said side members to extend across the bottom of said burner box space.

7. The method of assembling a cooktop of claim 1 wherein said terminal means of the surface heating elements are secured to the tray.

8. The method of assembling a cooktop of claim 1 wherein said burner box side members include a dividing wall member dividing said burner box space into two portions and said tray is secured to said dividing wall member.

9. The method of assembling a cooktop of claim 1 wherein the assembly is formed with the frame lowermost whereby the cooktop is inverted during said as sembly.

10. The method of assembling a cooktop electric heating coil to a mounting tray comprising the steps of:

mounting said heating coil in an outer insulator;

abutting two spaced portions of the insulator with corresponding spaced portions of the tray;

urging a sharp retainer into said insulator at a third portion of the insulator substantially opposed to said spaced portions; and

securing said retainer to said tray.

11. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 further including the step of urging a second sharp retainer carried by the tray into said insulator.

12. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 further including the step of urging a second sharp retainer carried by the tray into said insulator at one of said spaced portions.

13. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 wherein said spaced portions of the insulator define flat surfaces.

14. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 further including the step of bringing terminalswhich are electrically connected to said heating coil outwardly through a bottom wall of the tray. 

1. The method of assembling a cooktop comprising the steps of: providing a cooktop frame member in an inverted position; placing a glass-ceramic panel member on said frame; securing burner box side members to the frame to define a burner box space and retain the panel member thereto; subassembling a plurality of surface heating elements each including terminal means; attaching said plurality of the subassembled surface elements to a tray; placing the tray assembly in an inverted disposition in said burner box space with said surface elements bearing against the plate member; fastening the tray assembly to the burner box side members; and connecting electrical wires to the terminal means.
 2. The method of assembling a cooktop of claim 1 further including the step of mounting a gasket to the periphery of said plate member prior to placing it in said frame, and causing said burner box side members to retain the gasket to the frame.
 3. The method of assembling a cooktop of claim 1 further including the step of placing a control panel on said frame adjacent said panel member, and securing said control panel thereto by means of said burner box side members.
 4. The method of assembling a cooktop of claim 1 wherein said tray assembly is adjustably fixedly secured to said burner box side members.
 5. The method of assembling a cooktop of claim 1 further including the step of providing an electrical cable clamp through which said electrical wires are passed.
 6. The method of assembling a cooktop of claim 1 further including the step of securing a bottom wall to said side members to extend across the bottom of said burner box space.
 7. The method of assembling a cooktop of claim 1 wherein said terminal means of the surface heating elements are secured to the tray.
 8. The method of assembling a cooktop of claim 1 wherein said burner box side members include a dividing wall member dividing said burner box space into two portions and said tray is secured to said dividing wall member.
 9. The method of assembling a cooktop of claim 1 wherein the assembly is formed with the frame lowermost whereby the cooktop is inverted during said assembly.
 10. The method of assembling a cooktop electric heating coil to a mounting tray comprising the steps of: mounting said heating coil in an outer insulator; abutting two spaced portions of the insulator with corresponding spaced portions of the tray; urging a sharp retainer into said insulator at a third portion of the insulator substantially opposed to said spaced portions; and securing said retainer to said tray.
 11. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 further including the step of urging a second sharp retainer carried by the tray into said insulator.
 12. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 further including the step of urging a second sharp retainer carried by the tray into said insulator at one of said spaced portions.
 13. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 wherein said spaced portions of the insulator define flat surfaces.
 14. The method of assembling a cooktop electric heating coil to a mounting tray of claim 10 further including the step of bringing terminals which are electrically connected to said heating coil outwardly through a bottom wall of the tray. 